Asthma Introduction  
 

 

 

Heliox

 


 

Heliox is a mixture of helium and oxygen, with not less than 20 % oxygen. Usual combination ratio is 70 parts helium to 30 parts oxygen or 79 parts helium to 21 parts oxygen.

Heliox has been used for more than 70 years in medical applications and is widely used in diving applications. Heliox as a breathable gas for medical treatment in pulmonary disease was first introduced in 1934 by Barach.

Helium is one of the lightest gas, and it replaces nitrogen present in air which is much heavier. Helium is an inert gas i.e. it does not react with other substances. As Heliox is three times lighter than air, is easier to breath and faces much less resistance in airways.

Heliox is administered in a similar fashion as any other breathing gas. Heliox can be given by high flow nasal cannula, hood or facemask. Room air should not enter heliox breathing system as that will dilute the gas and increase its density.

Heliox can be used for jet nebulization. As heliox is a lighter gas, high flow rates are needed to produce medically useful aerosol.

Uses of Heliox:

Beneficial effects have been observed in patients with:

  • Croup
  • Bronchial asthma
  • COPD
  • Acute airway obstruction
  • Epiglottitis
  • Laryngitis
  • Tracheitis
  • Stridor
  • Foreign body aspiration
  • Tracheomalacia/stenosis
  • Cystic fibrosis
  • Bronchiectasis

  • Risks with Heliox system:

    Hypothermia.

    Infants who are administered Heliox via hood face risk of hypothermia. Heliox has high thermal conductivity and there is consequent risk of hypothermia when the gas temperature is 36C, especially when heliox is administered for long periods. The risk of hypothermia can be avoided with adequate warming and humidification of the heliox, using standard devices.

    Hypoxia.

    Faulty gas mixture containing less than 20 % oxygen is the cause for hypoxia. This risk is reduced by never administering 100% helium to a closed system, and always using heliox that contains at least 20% oxygen. Oxygen monitor in a breathing system should always be used.

    Delivery of Too Much Volume.

    If the mechanical ventilator delivers more than the set volume, there is a risk of volume-induced injury, pressure induced injury, or hypocarbia. This is of particular concern with ventilators not designed for heliox administration.

    Improper nebulization.

    Running a jet nebulizer with too low a flow of heliox can result in inadequate aerosol delivery to the patient at a time when aerosol delivery is critical.

     

     

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    Last edited 02-8-2010